I would like to get recommendations by experience tax preparers as to what tax software to use in my first year in the business.

I would suggest Taxact professional. You can find it on their site. It has everything you need and is the most user friendly. Taxact.com

I agree; TaxAct is your best choice. It is relatively inexpensive and pretty intuitive to use.

I suggest you pay as you go for the efile option because it is unlikely you will enough clients to justify pre-paying. After a set point of buying as you go, TaxAct allows you unlimited efiles at no additional cost.